Crossbow buttstock



FIG. 1 is a side perspective view of a crossbow buttstock.

FIG. 2 is a back perspective view of the crossbow buttstock shown in FIG. 1.

FIG. 3 is a left side view of the crossbow buttstock shown in FIG. 1; and,

FIG. 4 is a right side view of the crossbow buttstock shown in FIG. 1.

The broken lines depict portions of the crossbow buttstock and environmental structure and form no part of the claimed design. 

CLAIM The ornamental design for a crossbow buttstock, as shown and described. 